Track shunting apparatus



Patented Oct. 13, 1936 PATENT OFFICE TRACK SHUNTING APPARATUS Paul P. Sosinski, Edgewood, Pa., assignor to The Union Switch, & Signal Company, Swissvale,

Pa., a corporation of Application March 29,

9 Claims.

My invention relates to track shunting apparatus, and more particularly to apparatus for providing track circuit shunting by light weight rail vehicles.

I will describe two forms of apparatus embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawing, Fig. 1 is a diagrammatic view showing one form of apparatus embodying my invention; Fig. 2 is a diagrammatic view showing a modified form of the apparatus illustrated in Fig. 1, also embodying my invention.

Similar reference characters refer to similar parts'in both views.

In making use of the principle of applying a film breakdown voltage across the resistance film usually present ontherail surface, to aid shuntingof the track by light weight rail vehicles, it is customary to use rail brushes orother rail contacting devices for conducting the film. breakdown current as well as for providing an auxiliary shunting path from one tothe other rail. The apparatus herein disclosed shows a method whereby the wheels and axles of the car itself provide a path for the film breakdown current, thus utilizing the high rail contact pressure effective at a wheelof the vehicle, and making available a direct axle path of low res'istance from oneto the other rail, for shunting purposes.

.Referring to Fig. 1, the reference characters I andz designate the two rails of a section of track which is 'occupied by a steel wheeled rail vehicle, represented diagrammatically, by the axles 3, and 4, and wheels}, 6, l and 8. Axles 31 and 4, with their associated wheels, form a conducting path from one to the other railof the track, and have mounted thereon slip rings I ,9 and 10, respectively, byfmeans of which auxiliary current is conducted into the two axles. This auxiliary film breakdown current is supplied from the secondary winding ll of a transformer T, the. primarywinding 12 of which is energized fromthe alternating current. generatonG, througha current limiting reactor X. The {generator (3r is driven by a motor M, which is supplied with current from the car battery CB. :"When winding ll of transformer T is energi'zed, filmbreakdown current will flow through wire l3 andslip ring. 9, at which point it will dividIbetweentwo paths. One portion of this current will flow through one half of axle 3, wheel .5, rail Lwheel I, one half of axle 4, slip it new; a'nd wir'e 14 b k i W ing Th Pennsylvania 1933, Serial No. 663,310

remaining portion of the current will flow through the other half of axle 3, wheel 6, rail .2, wheel 8, and the other half of axle 4. The current from winding ll flowing in the above two paths will break down the rail contact resistance at wheels 5, 6, 1 and 8, and will maintain a low resistance shunting path from rail to rail, through each of the two axles. The axles 3 and 4 should preferably be insulated from the car body in order that the breakdown current 10 will be confined to the two rail paths.

In order to check that breakdown current of the proper magnitude for satisfactory shunting is flowing in both rail paths, I have provided a two-element alternating current relay 15 K, one element of which is energized from winding I5 on the axle transformer T and the other element of which is energized from winding 16 on the axle transformer 'I' through a split-phasing resistor R. Since the maximum value of the current delivered by winding II of transformer T is limited by reactor X, and since relay K will have the greatest torque when the currents in the two rail paths are equally divided, relay K can be made to release when a predetermined unbalance of the two currents occurs. That is, when the current in either path falls below a safe value, indicating that the film resistance has not been broken down sufiiciently in that path, relay K will release, opening its front contact I! to extinguish the indicator L. The car operator will then know that inadequate shunting protection is being provided and will take suitable action to protect the car. As soon as substan- 35 tially equal current division is restored in the two rail paths, relay K will pick up, lighting the indicator L.

To aid in restoring the proper current division, following the release of relay K, back contact is of this relay may be used to shunt the series reactor X, through a protective resistor R of low resistance, thereby increasing the potential applied across the collector rings 9 and I0 for more effective breakdown of the rail film in the higher resistance rail path. Also, back contact IQ of relay K may be used to close a direct current circuit from battery CB to winding 25 onthe transformer T, for introducing a substantial value of unidirectional flux into this transformer in order to introduce harmonics in the output voltage of winding II. The result of higher harmonics in the current which flows in the rail path wherein the resistance film has been broken down is to enable a higher voltage to be maintained across collector rings 9 and Ill due to the increased impedance of this rail path, occasioned by the higher frequency harmonics. As the frequency of the current supplied to collector rings 9 and I is increased, the drop across the rail portion of the path will also increase due to both inductance and skin effects, but the drop across the film resistance portions of the path will not change appreciably. Consequently, if a voltage of sufficiently high frequency is delivered by generator G, a potential above the value required for film breakdown can be maintained across the slip rings 9 and ID at all times, irrespective of whether the film resistance in one or the other path has or has not been broken down, the iron path acting to absorb most of the applied potential.

Referring to Fig. 2, the apparatus therein disclosed is similar to the apparatus of Fig. 1-, except that a separate high frequency generator G is provided for maintaining a suificiently high voltage for film breakdown notwithstanding complete breakdown of the film in one or the other rail path. Generator G supplies a substantial current at a frequency in the order of several hundred cycles per second, for example, to maintain a low resistance shunting path once the rail film has been broken down. Generator Gr is a low current, high frequency generator, the frequency being in the order of several thousand cycles per second. Winding 23 of transformer T supplies a high voltage at negligible current for film breakdown, whereas winding 2| of transformer T supplies a high current at low voltage for maintaining the low resistance shunt path. Reactor X and condenser C act as current limiting impedances and also confine the high and low frequency currents to their proper paths. The use of two separate generators in the above manner results in a substantial power saving, economizing the current of battery CB.

The equipment illustrated may be duplicated at each end of the car, in order to provide protection at such times also as when axles 3 and 4 of the car are located on opposite sides of an insulated rail joint.

If wheels having an insulated steel shell or tread member are used, the two tread members may be suitably connected together by a conductor of low resistance, this conductor serving as the primary for the indication transformers T and T in the same manner that the axle 3 of the drawing serves this purpose for the steel wheeled car.

I do not claim as my invention the means for increasing the voltage applied to the breakdown circuit or for increasing the short circuit current therein, as such inventions are disclosed and claimed in the copending applications, Serial No. 629,030, filed August 16, 1932, by Howard A. Thompson, and Serial No. 678,629, filed July 1, 1933, by Bernard E. OHagan, respectively. Also, I do not claim as my invention the use of two sources, one of high potential and low current capacity and the other of low potential and high current capacity for maintaining a low resistance track shunting path without an excessive expenditure of energy, as such invention is disclosed and claimed in the copending application, Serial No. 650,300, filed January 5, 1933, by Charles W. Butler and Bernard E. OHagan.

Although I have herein shown and described only two forms of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination with a section of railway track and a rail vehicle, two track shunts for said track, each including a pair of running wheels of the vehicle and an axle electrically insulated from the vehicle body, a source of current on the vehicle, two rail film breakdown paths one of which includes said source and one half of each of said two track shunts with the rail portion therebetween, and the other of which includes said source and the remaining half of each of said two track shunts with the rail portion therebetween, and an indicator responsive to the flow of breakdown current in both said paths for providing an indication when the rail film at both wheels of said two track shunts has been broken down.

2. In combination with a section of railway track and a rail vehicle, two track shunts for said track, each including a pair of running wheels of the vehicle and an axle electrically insulated from the vehicle body, a source of current on the vehicle, two rail film breakdown paths one of which includes said source and one half of each of said two track shunts with the rail portion therebetween, and the other of which includes said source and the remaining half of each of said two track shunts with the rail portion therebetween, and a two-element indicating relay one element of which becomes energized when breakdown current from said source flows in one of said two paths, and the other element of which becomes energized when breakdown current from said source flows in the other of said two paths.

3. In combination with a section of railway track and a rail vehicle, two track shunts for said track, each including a pair of running wheels of the vehicle and an axle electrically insulated from the vehicle body, of a source of varying current on the vehicle, two rail film breakdown paths one of which includes said source and one half of each of said two track shunts with the rail portion therebetween, and the other of which includes said source and the remaining half of each of said two track shunts with the rail portion therebetween, a two-element alternating current indication relay, a first axle transformer for one of said two paths having a winding connected with one element of said indication relay, a second axle transformer for the other of said two paths having a winding connected with the other element of said indication relay, and means for split-phasing the current supplied from said second transformer to said other element of the relay whereby the relay will provide an indication when breakdown currents from said source flow in both of said paths.

4. In combination with a section of railway track and a rail vehicle, two track shunts for said track, each including a pair of running wheels of the vehicle and an axle electrically insulated from the vehicle body, a source of relatively high frequency current on the vehicle, and means for conducting rail film breakdown current from said source over two paths, one of which includes the rail portion between two of said wheels and the other of which includes the rail portion between the other two of said wheels, the frequency of said source being sufliciently high to cause the rail impedance in said two paths to absorb a large part of the potential drop resulting from the flow of said film breakdown current whereby the breakdown of the rail film in one of said two paths will not materially decrease the voltage available for causing a breakdown in the other of said two paths.

5. In combination with a section of railway track and a rail vehicle, two track shunts for said track, each including a pair of running wheels of the vehicle and an axle electrically insulatedfrom the vehicle body, a first source of alternating current and a second source of direct current both on the vehicle, a transformer having aprimary energized from said first source and having a secondary, two rail film breakdown paths one of which includes said secondary and one half of each of said two track shunts with the rail portion therebetween, and the other of which includes said secondary and the remaining half of each of said two track shunts with the rail portion therebetween, a third winding on said transformer, and means for at times energizing said third winding from said second source to cause direct current saturation in said transformer for increasing the harmonics in the voltage of said secondary thereby aiding to maintain a film breakdown potential across said two paths.

6. In combination with a section of railway track and a rail vehicle, two track shunts for said track, each including a pair of running wheels of the vehicle and an axle electrically insulated from the vehicle body, a source of current on the vehicle, two rail film breakdown paths one of which includes said source and one half of each of said two track shunts with the rail portion therebetween, and the other of which includes said source and the remaining half of each of said two track shunts with'the rail portion therebetween, an indication relay which becomes energized when film breakdown currents from said source flow in both of said paths, and means governed by said indication relay for increasing the potential from said source available across said two paths when said relay is deenergized.

'7. In combination with a section of railway track and a rail vehicle, two track shunts for said track, each including a pair of running wheels of the vehicle and an axle electrically insulated from the vehicle body, a first source of alternating current and a second source of direct current both on the vehicle, a transformer having a primary energized from said first source and having a secondary, two rail film breakdown paths one of which includes said secondary and one half of each of said two track shunts with the rail portion therebetween, and the other of which includes said secondary and the remaining half of each of said two track shunts with the rail portion therebetween, an indication relay which becomes energized when film breakdown currents from said first source fiow in both of said paths, a third winding on said transformer, and a circuit including a back contact of said indication relay for energizing said third winding from said second source to cause direct current saturation in said transformer for increasing the harmonics in the voltage of said secondary thereby aiding to maintain a film breakdown potential across said two paths.

8. In combination with a section of railway track and a rail vehicle, two track shunts for said track, each including a pair of running wheels of the vehicle and an axle electrically insulated from the body of the vehicle; a first alternating current source of relatively high voltage, high frequency and low current on the vehicle; a second alternating current source of relatively low voltage, low frequency and high current in parallel with said first source; and two rail film breakdown paths one of which includes said two sources and one half of each of said two track shunts with the rail portion therebetween, and the other of which includes said two sources and the remaining half of each of said two track shunts with the rail portion therebetween, said first source acting to maintain a relatively high film breakdown potential across both of said paths and said second source acting to cause a relatively high film breakdown current to flow in each of said two paths when the rail film has been broken down by the potential from said first source.

9. In combination with a section of railway track and a rail vehicle, two track shunts for said track, each including a pair of running wheels of the vehicle and an axle electrically insulated from the body of the vehicle; a first alternating current source of relatively high voltage, high frequency and low current on the vehicle; a second alternating current source of relatively low voltage, low frequency and high current in parallel with said first source; a condenser in series with said first source and a reactor in series with said second source for decreasing the interchange of current between said two sources, two rail film breakdown paths one of which includes said two sources and one half of each of said two track shunts with the rail portion therebetween, and the other of which includes said two sources and the remaining half of each of said two track shunts with the rail portion therebetween, said first source acting to maintain a relatively high film breakdown potential across both of said paths and said second source acting to cause a relatively high film breakdown current to fiow in each of said two paths when the rail film has been broken down by the potential from'said first source, and an indication relay which becomes energized when currents from said second source fiow in both of said paths.

PAUL P. SOSINSKI. 

